Presently, the screw driver is widely used and is indispensable in nearly every business and family. However, the screws, screw bolts, and flutes of the screws applied to the articles are varied in sizes or types. The screw drivers to have to be provided in full sets, each set of which is distinguished with screw drivers of the specific sizes or types to meet the specific screw. Yet to non-professional members such as in a family, such complete set provision is unlikely, so there arises occasions where some screws will to be difficult to handle.
Assembled screw drivers are known in the market which bring full sets to the non-professional members. The devices use a driving rod whose front end is provided with a clamper to clamp driving head and which is packed with some driving heads in different sizes or types, altogether as a full set. In use, it needs to get the chosen driver head locked inside the clamper. However, because of small dimension of the driving head, there is still drawback that it is easy to get lost and hard to find.